This circuit operates at a frequency of 80 KHz and modulation up to 60 kHz. The circuit is from 1980s documentation. The PUT is an uncommon component today.
This amplifier with gain control was obtained in a documentation from Signetics of the 80's....
November 2016 - Mouser Electronics is indicating in its inventories the new NXP Kinetis L MCUs....
This circuit uses an 18 MHz crystal to generate 36 MHz signals. We found it in an 80's...